- adding back Serg's "mtr --list-options"
- safe_mutex deadlock detector started raising wrong deadlock warnings, fixed
here by a backport from 6.0-main.

include/my_pthread.h:
  Porting changes done to 6.0-main which satisfy the safe_mutex deadlock detector (those
  in 5.1-main don't), see chad@mysql.com-20090126155607-n0j3zbmgbfepnmmo for explanations
mysql-test/mysql-test-run.pl:
  adding back Serg's --list-options
mysys/my_init.c:
  Porting changes done to 6.0-main which satisfy the safe_mutex deadlock detector (those
  in 5.1-main don't), see chad@mysql.com-20090126155607-n0j3zbmgbfepnmmo for explanations
mysys/my_thr_init.c:
  Porting changes done to 6.0-main which satisfy the safe_mutex deadlock detector (those
  in 5.1-main don't), see chad@mysql.com-20090126155607-n0j3zbmgbfepnmmo for explanations